Because they are getting the business outcome they want
That is the key point on why they don't care. Because the technology is providing them with what they want. They couldn't care less whether its a new shiny implementation using REST or some clunky old solution using string, spit and a bloke called Dave with hammers.
All too often IT folks make the mistake of trying to develop and "operationally perfect" solution from a technical perspective but which takes longer to get there from a business perspective, thus meaning that its perceived by the business as a failure and all they are hearing from IT is a list of wonderful technologies which are the reason why they aren't getting their business outcome.
The same goes when the programme goes over budget due to the customisations of the package or the unexpected complexities of the cloud solution. The excuses are almost always technical but all the business cares about is the outcome.
So next time you are looking at the architecture and thinking REST, WS, Dynamically scalable et al just ask yourself this simple question
If I made it simpler and didn't aim for technical perfection would I deliver the business outcome quicker?
Because the business doesn't care how you do it... just that it is done